=act,per additional test for onTransition behaviour when initialize() called

akka-persistence/src/main/scala/akka/persistence/fsm/FSM.scala

@@ -503,7 +503,9 @@ trait FSM[S, D, E] extends Actor with Listeners with ActorLogging {
   /**
    * Verify existence of initial state and setup timers. This should be the
    * last call within the constructor, or [[akka.actor.Actor#preStart]] and
-   * [[akka.actor.Actor#postRestart]]
+   * [[akka.actor.Actor#postRestart]].
+   *
+   * An initial `currentState -> currentState` notification will be triggered by calling this method.
    *
    * @see [[#startWith]]
    */

akka-persistence/src/test/scala/akka/persistence/PersistentActorSpec.scala

@@ -678,7 +678,7 @@ abstract class PersistentActorSpec(config: Config) extends PersistenceSpec(confi
       persistentActor ! GetState
       expectMsg(List("a-1", "a-2", "b-10", "b-11", "b-12", "c-10", "c-11", "c-12"))
     }
-    "recover on command failure xoxo" in {
+    "recover on command failure" in {
       val persistentActor = namedPersistentActor[Behavior3PersistentActor]
       persistentActor ! Cmd("b")
       persistentActor ! "boom"

akka-persistence/src/test/scala/akka/persistence/fsm/PersistentFSMActorSpec.scala

@@ -223,6 +223,20 @@ abstract class PersistentFSMActorSpec(config: Config) extends PersistenceSpec(co
         expectTerminated(recoveredFsmRef)
       }
     }
+
+    "not trigger onTransition for stay()" taggedAs TimingTest in {
+      val persistenceId = name
+      val probe = TestProbe()
+      val fsmRef = system.actorOf(SimpleTransitionFSMActor.props(persistenceId, probe.ref))
+
+      probe.expectMsg(3.seconds, "LookingAround -> LookingAround") // caused by initialize(), OK
+
+      fsmRef ! "goto(the same state)" // causes goto()
+      probe.expectMsg(3.seconds, "LookingAround -> LookingAround")
+
+      fsmRef ! "stay" // causes stay()
+      probe.expectNoMsg(3.seconds)
+    }
   }
 
 }
@@ -281,6 +295,28 @@ object PersistentFSMActorSpec {
   case class PurchaseWasMade(items: Seq[Item]) extends ReportEvent
   case object ShoppingCardDiscarded extends ReportEvent
 
+  class SimpleTransitionFSMActor(_persistenceId: String, reportActor: ActorRef)(implicit val domainEventClassTag: ClassTag[DomainEvent]) extends PersistentFsmActor[UserState, ShoppingCart, DomainEvent] {
+    override val persistenceId = _persistenceId
+
+    startWith(LookingAround, EmptyShoppingCart)
+
+    when(LookingAround) {
+      case Event("stay", _) ⇒ stay
+      case Event(e, _)      ⇒ goto(LookingAround)
+    }
+
+    onTransition {
+      case (from, to) ⇒ reportActor ! s"$from -> $to"
+    }
+
+    override def applyEvent(domainEvent: DomainEvent, currentData: ShoppingCart): ShoppingCart =
+      currentData
+  }
+  object SimpleTransitionFSMActor {
+    def props(persistenceId: String, reportActor: ActorRef) =
+      Props(new SimpleTransitionFSMActor(persistenceId, reportActor))
+  }
+
   class WebStoreCustomerFSMActor(_persistenceId: String, reportActor: ActorRef)(implicit val domainEventClassTag: ClassTag[DomainEvent]) extends PersistentFsmActor[UserState, ShoppingCart, DomainEvent] {
     override def persistenceId = _persistenceId